From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jim Mattson Subject: Re: [PATCH v2] kvm: nVMX: VMCLEAR an active shadow VMCS after last use Date: Wed, 2 Nov 2016 10:56:39 -0700 Message-ID: References: <1477668579-22555-1-git-send-email-jmattson@google.com> <3b4e2b95-530d-4a69-14c7-4f622478560b@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: kvm@vger.kernel.org, Bandan Das , David Matlack , Peter Feiner To: Paolo Bonzini Return-path: Received: from mail-vk0-f47.google.com ([209.85.213.47]:33979 "EHLO mail-vk0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756394AbcKBR4l (ORCPT ); Wed, 2 Nov 2016 13:56:41 -0400 Received: by mail-vk0-f47.google.com with SMTP id x186so19469024vkd.1 for ; Wed, 02 Nov 2016 10:56:41 -0700 (PDT) In-Reply-To: <3b4e2b95-530d-4a69-14c7-4f622478560b@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Sorry; I changed the title after reworking the patch. V1 was "[PATCH] kvm: nVMX: Track active shadow VMCSs" (15 July 2016). On Wed, Nov 2, 2016 at 10:23 AM, Paolo Bonzini wrote: > On 28/10/2016 17:29, Jim Mattson wrote: >> After a successful VM-entry with the "VMCS shadowing" VM-execution >> control set, the shadow VMCS referenced by the VMCS link pointer field >> in the current VMCS becomes active on the logical processor. >> >> A VMCS that is made active on more than one logical processor may become >> corrupted. Therefore, before an active VMCS can be migrated to another >> logical processor, the first logical processor must execute a VMCLEAR >> for the active VMCS. VMCLEAR both ensures that all VMCS data are written >> to memory and makes the VMCS inactive. >> >> Signed-off-by: Jim Mattson >> Reviewed-By: David Matlack > > The patch looks good but---sorry for the possibly stupid > question---where was v1? > > Paolo > >> --- >> arch/x86/kvm/vmx.c | 22 +++++++++++++++------- >> 1 file changed, 15 insertions(+), 7 deletions(-) >> >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> index cf0b7be..046b03f 100644 >> --- a/arch/x86/kvm/vmx.c >> +++ b/arch/x86/kvm/vmx.c >> @@ -187,6 +187,7 @@ struct vmcs { >> */ >> struct loaded_vmcs { >> struct vmcs *vmcs; >> + struct vmcs *shadow_vmcs; >> int cpu; >> int launched; >> struct list_head loaded_vmcss_on_cpu_link; >> @@ -411,7 +412,6 @@ struct nested_vmx { >> * memory during VMXOFF, VMCLEAR, VMPTRLD. >> */ >> struct vmcs12 *cached_vmcs12; >> - struct vmcs *current_shadow_vmcs; >> /* >> * Indicates if the shadow vmcs must be updated with the >> * data hold by vmcs12 >> @@ -1419,6 +1419,8 @@ static void vmcs_clear(struct vmcs *vmcs) >> static inline void loaded_vmcs_init(struct loaded_vmcs *loaded_vmcs) >> { >> vmcs_clear(loaded_vmcs->vmcs); >> + if (loaded_vmcs->shadow_vmcs && loaded_vmcs->launched) >> + vmcs_clear(loaded_vmcs->shadow_vmcs); >> loaded_vmcs->cpu = -1; >> loaded_vmcs->launched = 0; >> } >> @@ -3562,6 +3564,7 @@ static void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs) >> loaded_vmcs_clear(loaded_vmcs); >> free_vmcs(loaded_vmcs->vmcs); >> loaded_vmcs->vmcs = NULL; >> + WARN_ON(loaded_vmcs->shadow_vmcs != NULL); >> } >> >> static void free_kvm_area(void) >> @@ -6696,6 +6699,7 @@ static struct loaded_vmcs *nested_get_current_vmcs02(struct vcpu_vmx *vmx) >> if (!item) >> return NULL; >> item->vmcs02.vmcs = alloc_vmcs(); >> + item->vmcs02.shadow_vmcs = NULL; >> if (!item->vmcs02.vmcs) { >> kfree(item); >> return NULL; >> @@ -7072,7 +7076,7 @@ static int handle_vmon(struct kvm_vcpu *vcpu) >> shadow_vmcs->revision_id |= (1u << 31); >> /* init shadow vmcs */ >> vmcs_clear(shadow_vmcs); >> - vmx->nested.current_shadow_vmcs = shadow_vmcs; >> + vmx->vmcs01.shadow_vmcs = shadow_vmcs; >> } >> >> INIT_LIST_HEAD(&(vmx->nested.vmcs02_pool)); >> @@ -7174,8 +7178,11 @@ static void free_nested(struct vcpu_vmx *vmx) >> free_page((unsigned long)vmx->nested.msr_bitmap); >> vmx->nested.msr_bitmap = NULL; >> } >> - if (enable_shadow_vmcs) >> - free_vmcs(vmx->nested.current_shadow_vmcs); >> + if (enable_shadow_vmcs) { >> + vmcs_clear(vmx->vmcs01.shadow_vmcs); >> + free_vmcs(vmx->vmcs01.shadow_vmcs); >> + vmx->vmcs01.shadow_vmcs = NULL; >> + } >> kfree(vmx->nested.cached_vmcs12); >> /* Unpin physical memory we referred to in current vmcs02 */ >> if (vmx->nested.apic_access_page) { >> @@ -7352,7 +7359,7 @@ static void copy_shadow_to_vmcs12(struct vcpu_vmx *vmx) >> int i; >> unsigned long field; >> u64 field_value; >> - struct vmcs *shadow_vmcs = vmx->nested.current_shadow_vmcs; >> + struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs; >> const unsigned long *fields = shadow_read_write_fields; >> const int num_fields = max_shadow_read_write_fields; >> >> @@ -7401,7 +7408,7 @@ static void copy_vmcs12_to_shadow(struct vcpu_vmx *vmx) >> int i, q; >> unsigned long field; >> u64 field_value = 0; >> - struct vmcs *shadow_vmcs = vmx->nested.current_shadow_vmcs; >> + struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs; >> >> vmcs_load(shadow_vmcs); >> >> @@ -7591,7 +7598,7 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu) >> vmcs_set_bits(SECONDARY_VM_EXEC_CONTROL, >> SECONDARY_EXEC_SHADOW_VMCS); >> vmcs_write64(VMCS_LINK_POINTER, >> - __pa(vmx->nested.current_shadow_vmcs)); >> + __pa(vmx->vmcs01.shadow_vmcs)); >> vmx->nested.sync_shadow_vmcs = true; >> } >> } >> @@ -9156,6 +9163,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) >> >> vmx->loaded_vmcs = &vmx->vmcs01; >> vmx->loaded_vmcs->vmcs = alloc_vmcs(); >> + vmx->loaded_vmcs->shadow_vmcs = NULL; >> if (!vmx->loaded_vmcs->vmcs) >> goto free_msrs; >> if (!vmm_exclusive) >>